Warning light with dim-light display



Nov. 8, 1955 T. w. HALLERBERG Erm.

WARNING LIGHT WITH DIM-LIGHmIsPLAY Filed Aug. s, 1954 United States Patent() 2,123,389 Y WARNING LIGHT WITH DIM-LIGHT DISPLAY Theodore W. Hallerberg, Los Angeles, Roy L. Roberts, Jr., Fullerton, and Herman H. Flum, South Gate, Calif.; aig Roberts, Jr., and said Flum assignors to said Haler erg Application August 9, 1954, Serial No. 448,548

2 Claims. (Cl. 340-252) This invention relates to warning lights of the type used in aircraft or the like to indicate a failure or misfunction of an operating device or mechanism. The primary object of the invention is to provide a simple and ecient device which gives an initial warning by means of a subdued light and thereafter a warning by means of a bright light in the event that the operator has disregarded the initial warning.

Other objects and advantages of the invention will become apparent from the following detailed specification describing a preferred embodiment thereof, reference being had to the accompanying drawings in which- Fig. l is a central vertical sectional view,4partially diagrammatic of a warning light embodying the present invention;

Fig. 2 is a somewhat diagrammatic circuit diagram;

Fig. 3 is a fragmentary view of certain of the parts in the position occupied when the display of the warning lamp is bright, and

Fig. 4 is a view similar to Fig. 3 showing the parts latched in the position in which the display of the warning lamp is dim.

Referring to Fig. 1, a device embodying the present invention is there shown as including a housing 1 which may be held in place with respect to a bulkhead or instrument panel by gland nuts 2 and 3 threaded over an end of the housing and clamping the entire instrument in place. At its outer end, the housing is formed to slidingly receive a lens assembly comprising a tubular insulating body 5 having a threaded outer end to which a lens 6 is attached, the lens carrying an operating ring 7 for the convenience of the operator. A nger extension 8 of the insulating body 5 is passed along one side wall of the housing interior and engages a disk-like contact member 10 which is biased outwardly by a spring 12, the spring also acting as a current carrying element as hereinafter described. The spring 12 serves to maintain the entire lens assembly in an outward or extended position from which it can be moved whenever the operator presses against it for purposes of testing or dimming the display of the warning light as will be later described.

The housing 1 is lined by a tube of insulation 14 at one end of which is carried a partition 16. A lamp socket 1S is xed to the partition, being disposed over a contact plate 20 and also over an inturned end of a first bimetallic arm 22 which extends inwardly from the partition and along one side of the housing. A lamp 24 is connected to and held in place in the socket 18 in any suitable manner as by the usual pin 26 on the lamp base so that the lamp is electrically connected at its shell contact to the bimetallic arm and to the contact plate 20.

The lamp socket is preferably fixed to the partition by a rivet 28 turned over an insulating grommet 29 at its outer side and passedA through an insulating tube 30. At its inner side the rivet is turned over a depending contact 32and xes in place a yoke 34, as well as a second birnetallic arm 35. The yoke 34 is insulated from contact 32l bya disk 36. The rivet 28 being itself a tubular member, it is utilized to receive a spring pressed center lamp contacting plunger 38 which is thus electrically connected to the depending contact 32 and to the center contact of the lamp. A small spring 40 biases the plunger 38 outwardly against the lamp.

At its inner end the yoke 34 has a radial extension 42 to which is adjustably connected a contact screw 44 which thus forms a stationary contact of a switch which will be hereinafter described.

Contact member 10 is formed with a disk-like portion above which is a cylindrical extension which forms a side contact 46. Above the contact member and its side contact is an insulating button 4S which has a shoulder 50 cut thereon. A depending tubular extension S2 of the contact member 10 guides the member and its associated parts for reciprocation in a cylindrical insulating member 54 which is preferably formed as a cup-like extension of a housing closure or base plate 56. The reciprocable assembly carries a Contact 58 at its center which is insulated from the depending tubular extension 52 and which receives current through a spring connector 60.

Contact 58 is reciprocable to and from the stationary contact screw 44 and cooperates therewith to form a switch which may be opened whenever the operator presses inwardly on the lens assembly ring 7 and thus moves the` contact member 10 inwardly through the movement of the linger 8.

The contact member 10 is adapted to form a movable portion of a testing switch, the stationary contact of which comprises a metallic stem 62 disposed in the path of movement of the contact 10.

Contact prongs A, B and C extend from the inner end of the unit and either comprise or are connected with contact 32, center spring contact 12, and test contact stem 62 respectively.

Turning now to the schematic diagram shown in Fig. 2, corresponding parts shown or indicated in Fig. l have been given corresponding reference numerals in Fig. 2 insofar as possible in the disclosure of the circuit. Power for the lamp 24 is supplied from a battery 80 and is controlled in general by a power switch 82. From power switch 82 connection is made to terminal C and thus to center contact 58 as Well as to the metallic stern 62 which forms the stationary contact of a test switch of which the contact assembly 10 is a part. The contact 44, which cooperates with contact 58, is in circuit with a coil 84 wound around and in heat transfer relationship with the second bimetallic arm 35 and constitutes, with contact 58, what will hereinafter be called the ready switch and controls the ow of current to what will hereinafter be called the ready winding or coil 84. The opposite end of the ready winding 84 is returned to the battery by lead 86 and terminal A.

The battery is connected to a function circuit including a function switch 88 which may be any known type of circuit closing device suitably responsive to the condition which it monitors. Thus the switch may be pressure actuated if it is to monitor pressure or thermally actuated if the condition which causes it to close is characterized by an increase or decrease of temperature.

The function switch 8S is connected by a lead 90 to terminal B of the warning device. Terminal B' is connected to two parallel circuits each of which contains a heating resistance associated with a bimetallic arm and is also connected by spring 12 (connection 92 in Fig. 2) to the body of contact 10. One of the aforementioned resistances is designated 94 in Fig. 2 and is called a hold lamp whenever the circuit thereto is completed through the resistance of the holding winding 94.

The other parallel circuit to which terminal B is connected includes a heating coil 98 disposed around the iirst bimetallic arm 22 but insulated therefrom, and returned to the battery by connection 1539. The heating coil 98 is called a bright winding for the reason that it serves to increase the temperature of the bimetallic arm 22 so as to cause it to deform from its normal position in which it is disengaged, into engagement with the cylindrical part 46 of the contact 10. The arm 22 being itself connected to the lamp by a lead 102, it will be seen that a low resistance circuit is established from terminal B to the lamp by way of lead 92, contact 10, arm 22 and lead 102 whenever the arm is electrically connected to the contact 10. The low resistance circuit thus formed shunts the dim, or higher resistance circuit from terminal B to the lamp which includes the resistance 94 and connection 96.

The operation of the device will now be described.

When power switch 82 is closed the unit may be immediately tested to determine the condition of the lamp 24 which is normally extinguished. For this purpose the operator pushes in on the protruding portion of the instrument by pressing against ring '7. This moves the insulating cylinder 5 and its extension finger S inwardly relative to the casing or housing 1. Finger 8 presses contact 10 inwardly until it cornes up against the metallic stem 62 which constitutes the stationary contact of the test switch. If the lamp 24 is in proper condition current now flows from the battery 80 to terminal C, to stem 62, contact 10, lead 92, through resistance 94 and lead 96 to the lamp, and from the lamp back via terminal A to the battery.

As soon as the power switch is closed a circuit is also established from terminal C through the ready switch contacts 53 and 44 to the resistance of ready winding 84 around the terminal arm 35. Arm 35 thus becomes heated and swings in against the insulating disk 48 in position to move in over shoulder 50 should the disk and its associated parts be moved inwardly by the operator. It will be seen that the disk will be retained in its lowered position so long as arm 35 is heated, but that the circuit to the ready winding will be broken by opening contacts 44 and 5E, contact 44 being stationary in the housing. The action of the thermal arm 35 is thus that of a latch member cooperating with the detent formed by shoulder 50.

During normal operation the lamp 24 shows no signal, but when function switch 88 is closed a circuit is immediately established which will cause the lamp to burn with a dim light. This circuit is from the battery, through the function switch 83, lead 90, resistance winding 94, lead 96 to the lamp 24. At the same time a parallel circuit is established through the bright Winding 98 around the thermal arm 22. Thus the thermal arm 22 also begins to heat up and to deform inwardly in the direction of contact 10 and the device is preferably so proportioned that about ten to fifteen seconds is required for the arm to deform sufficiently to make contact with the cylindrical extension 46 of the contact 10. This time factor can be varied by changing the resistance of the bright winding 98 or by changing the thickness, length, or material of the arm 22.

lf the operator fails to note the warning given by the initial dim light, a bright signal will be given to him as soon as the time has elapsed for the arm 22 to reach and make contact with the extension 46 of the contact 10. The bright circuit then established is from battery 80 through the function switch 88, lead 90, lead 92 to contact 10, via arm 22, lead 102 to the lamp.

If the operator notes the presence of the warning signal and does not wish to have the bright display, which may be annoying to him, or if the bright display has come on and he wishes to dim it, he can do so quickly and easily by pushing in on the protruding portion of the instrument in the same manner as he used for testing it. He thus pushes contact 10 down to such an extent that the arm 22 bears against the insulating member 43 in stead of the metallic extension 46 of the contact and the bright circuit is broken at this point. The contact assembly will thereafter be held down by the latch including arm 35 which has been heated and has been standing against the member 48 biased inwardly by the heat of winding 84 as well as winding 94. The arm 35 thus moves in over the shoulder 50 and will remain in this position in which it prevents the return of the contact 10 assembly so long as current continues to be supplied to the winding 94 by reason of the function switch being closed. Thereafter until the trouble or misfunction is cleared, or until the power from the battery is cut off the lamp 24 will continue to burn dim.

lf the function is cleared so that switch S8 is opened, all current to hold winding 94, which has been heating arm 35 and holding it in position over shoulder 50, is cut off. The arm then cools quickly, straightens and moves away from shoulder 50. When the arm has cleared the shoulder, spring 12 acts to restore the contact assembly 10 to its original position and the parts are ready to operate again if the misfunction recurs.

Similarly, at the end of a iiight the parts will be restored to their original position because the power switch 82 will be opened thus cutting off the flow of current to the winding 94 at this point.

While the invention has been disclosed in conjunction with a specific form and disposition of the parts it should be appreciated that various modilications and changes may be made without departing from the spirit of the appended claims.

We claim:

l. A warning device comprising in combination a power source, a power switch controlling said source, a warning lamp, a function switch responsive to a condition to be monitored and acting when closed to complete a first relatively high resistance circuit from said power source to said lamp and to complete a second circuit from said power source, means operated by said second circuit to establish after a predetermined time delay a relatively low resistance shunt circuit to said lamp around said iirst circuit, whereby said lamp displays a dim light when said function switch is rst closed and a brighter light after said predetermined time delay and the operation of said last means, manually operable means to open the low resistance circuit established by said last means, and a thermally energized latch means to hold said manually operable means in its open position.

2. A warning device comprising in combination a power source, a powerswitch controlling said source, a warning lamp, a function switch responsive to a condition to be monitored and acting when closed to complete a irst relatively high resistance circuit from said power source to said lamp and to complete a second circuit from said power source, a heating winding in said second circuit, a bimetallic Varm associated with said heating winding and connected to said lamp, and a movable contact connected to said function switch and associated with said bimetallic arm, said arm being normally out of engagement with said contact and moved into engagement therewith when heated by said heating Winding, to establish a relatively lower resistance shunt circuit to said lamp around said first circuit, whereby said lamp displays a dim light when said function switch is first closed and a brighter light after said thermal arm has engaged said contact, manually operable means to move said contact out of engagement with said bimetallic arm, and latch means to hold said contact in its out-of-engagement position, said latch means being energized only when said power switch is closed.

References Cited in the tile of this patent UNITED STATES PATENTS 2,519,368 Hallerberg Aug. 22, 1950 2,553,968 Hallerberg May 22, 1951 2,625,594 Mathis Ian. 13, 1953 

